Photosensitive adhesive composition, and obtained using the same, adhesive film, adhesive sheet, semiconductor wafer with adhesive layer, semiconductor device and electronic part

ABSTRACT

A photosensitive adhesive composition comprising: (A) a polyimide having a carboxyl group as a side chain, whereof the acid value is 80 to 180 mg/KOH; (B) a photo-polymerizable compound; and (C) a photopolymerization initiator.

RELATED APPLICATIONS

This is a Divisional application of application Ser. No. 11/969,358,filed Jan. 4, 2008 now U.S. Pat. No. 7,851,131, which is a continuationapplication of Application Serial No. PCT/JP2006/313114 filed on Jun.30, 2006. The contents of application Ser. No. 11/969,358 areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a photosensitive adhesive composition,adhesive film obtained using the same, adhesive sheet, semiconductorwafer with adhesive layer, and semiconductor device and electroniccomponents.

2. Related Background of the Invention

In recent years, due to the higher performance and higher functionalityof electronic components, various types of semiconductor package havebeen proposed. In semiconductor packages, adhesives for bonding asemiconductor device to a supporting substrate for mounting thesemiconductor device, and adhesives for bonding a semiconductor chip tovarious types of adherends, are required to have low stress, stickingproperty at low temperatures, wetproof reliability, and solder-proofreflow properties. In methods which simplify functions, forms andassembly processes for semiconductor packages or electronic parts, itmay also be required to have a photosensitive function which allowsformation of a pattern. Photosensitivity is a property whereby a partirradiated by light undergoes a chemical change, and becomes soluble orinsoluble in an aqueous solution or an organic solvent. If an adhesivehaving such photosensitivity is used, by exposing it via a photomask andforming a pattern with a developer solution, it is possible to obtain avery fine adhesive pattern. Until now, photosensitive adhesives werebased on a polyimide resin precursor (polyamide acid) or polyimide resin(JP-A No. 2000-290501, JP-A No. 2001-329233, JP-A No. 11-24257).However, in the former case, during a ring closure reaction to producethe imide, and in the latter case during the adhesion step, a hightemperature of 300° C. or more was required, so thermal damage tosurrounding material was severe. There was also the problem thatresidual heat stress was easily generated.

It has also been attempted to improve sticking property at lowtemperatures and solder heat resistance by blending and crosslinking athermosetting resin with an adhesive using a polyimide resin or thelike.

SUMMARY OF THE INVENTION

However, conventional photosensitive adhesives using a polyimide resindid not easily have both the ability to form a pattern with an alkalideveloper solution, and stick to an adherend at low temperature. Also,when bonded by thermocompression after light exposure, it was difficultto impart a re-adhesiveness which gave sufficiently high adhesivestrength.

It is therefore an object of the present invention to provide aphotosensitive adhesive composition having superior pattern-formingproperties with an alkali developer solution, and sufficientre-adhesiveness after light exposure. The invention further aims toprovide an adhesive film having superior pattern-forming properties withan alkali developer solution and sufficient re-adhesiveness after lightexposure which can also be stuck to an adherend at low temperatures. Itstill further aims to provide highly reliable semiconductor devices andelectronic components in which semiconductor chips are bonded withsuperior adhesive strength.

The photosensitive adhesive composition of the invention contains (A) apolyimide having a carboxyl group as a side chain, whereof the acidvalue is 80 to 180 mg/KOH, (B) a photo-polymerizable compound, and (C) aphotopolymerization initiator. The aforesaid acid value is preferably 80to 150 mg/KOH.

This photosensitive adhesive composition, by using a polyimide having acarboxyl group and an acid value within the aforesaid specific range,achieves both superior pattern-forming properties with an alkalideveloper solution and sufficient re-adhesiveness after exposure.

Alternatively, the photosensitive adhesive composition of the inventionmay contains (A) a polymer soluble to an alkaline aqueous solution, (B)a photo-polymerizable compound, and (C) a photopolymerization initiator.An adhesive pattern is formed by forming an adhesive layer consisted ofthe photosensitive adhesive composition on an adherend, light-exposingthe adhesive layer via a photomask, and developing the adhesive layerwith an alkaline aqueous solution after exposure. And another adherendcan be bonded to the adherend via the adhesive pattern. The polymersoluble to alkaline aqueous solution is preferably a polyimide having acarboxyl group as a side chain.

The photosensitive adhesive composition of the invention preferablyfurther contains (D) a thermosetting resin. This thermosetting resin ispreferably an epoxy resin.

The aforesaid polyimide is preferably a polyimide obtained by reacting atetracarboxylic acid dianhydride and diamine including an aromaticdiamine expressed by the following general formula (I) or (II):

From the viewpoint of pattern-forming properties with an alkalideveloper solution and film-forming properties, the weight averagemolecular weight of the polyimide is preferably 5000 to 150000.

The glass transition temperature of the polyimide is preferably 150° C.or less. Due to this, the adhesive film comprising the photosensitiveadhesive composition can be stuck to an adherend such as a semiconductorwafer at lower temperatures. For a similar reason, the aliphatic etherdiamine expressed by the following general formula (III) preferablyaccounts for 10 to 90 mole % of the total diamine:

In the formula, Q₁, Q₂ and Q₃ are independently alkylene groups having 1to 10 carbon atoms, and n₁ is an integer from 1 to 80.

In the aforesaid diamine, the siloxane diamine expressed by thefollowing general formula (IV) preferably accounts for 1 to 20 mole % ofthe total diamine:

In the formula, R₁ and R₂ are independently alkylene groups having 1 to5 carbon atoms or phenylene groups which may have a substituent, R₃, R₄,R₅ and R₆ are independently an alkylene group having 1 to 5 carbonatoms, phenyl group or phenoxy group, and n₂ is an integer from 1 to 5.

The molecular weight of the photo-polymerizable compound is preferably2000 or less. And the photosensitive adhesive composition of theinvention preferably contains the photo-polymerizable compound to anextent of 20 weight parts or more relative to 100 weight parts ofpolyimide.

When a silicon chip is bonded to a glass substrate via thephotosensitive adhesive composition of the invention, the photosensitiveadhesive composition preferably provides a shear adhesive strength of 5MPa or more at 25° C. Further, when a silicon chip is bonded to a glasssubstrate via the photosensitive adhesive composition of the invention,the photosensitive adhesive composition preferably provides a shearadhesive strength of 0.5 MPa or more at 260° C.

The storage modulus at 100° C. of the photosensitive adhesivecomposition after light exposure is preferably 0.01 to 10 MPa. Afterexposure, the storage modulus at 260° C. of the photosensitive resincomposition after heat curing is preferably 1 MPa or more.

After light exposure, the temperature at which the mass reduction of thephotosensitive adhesive composition is 5% in a thermogravimetricanalysis after heat curing, is preferably 260° C. or more.

The adhesive film of the invention comprises the aforesaidphotosensitive adhesive composition of the invention. The adhesive sheetof the invention comprises a substrate and the aforesaid adhesive filmof the invention on one surface thereof.

The adhesive pattern of the invention is formed by forming an adhesivelayer comprising the aforesaid photosensitive adhesive composition ofthe invention on an adherend, exposing this adhesive layer via aphotomask, and developing the adhesive layer with an alkaline aqueoussolution after exposure. Since the photosensitive adhesive compositionof the invention has superior pattern-forming properties, this adhesivelayer can have a very fine pattern, and has superior re-adhesivenessafter light exposure.

The semiconductor wafer with an adhesive layer of the inventioncomprises a semiconductor wafer and an adhesive layer comprising theaforesaid photosensitive adhesive composition of the invention on onesurface thereof.

The semiconductor device of the invention comprises a semiconductor chipbonded to an adherend using the aforesaid photosensitive adhesivecomposition of the invention. The electronic component of the inventioncomprises this semiconductor device.

The method of the invention for producing a semiconductor devicecomprises the steps of forming an adhesive pattern by forming anadhesive layer consisted of the photosensitive adhesive compositionaccording to claim 1 on an adherend, light-exposing the adhesive layervia a photomask, and developing the adhesive layer with an alkalineaqueous solution after exposure, and bonding another adherend to theadherend via the adhesive pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing an embodiment of an adhesivefilm according to the invention.

FIG. 2 is a cross-sectional view showing an embodiment of an adhesivesheet according to the invention.

FIG. 3 is a top view showing an embodiment of a semiconductor wafer withan adhesive layer according to the invention.

FIG. 4 is an end elevation along a line IV-IV in FIG. 3.

FIG. 5 is a top view showing an embodiment of an adhesive patternaccording to the invention.

FIG. 6 is an end elevation along a line VI-VI in FIG. 5.

FIG. 7 is a top view showing an embodiment of an adhesive patternaccording to the invention.

FIG. 8 is an end elevation along a line VIII-VIII in FIG. 7.

FIG. 9 is a top view showing a state where a cover glass is bonded to asemiconductor wafer via an adhesive pattern.

FIG. 10 is an end elevation along a line X-X in FIG. 9.

FIG. 11 is a top view showing a state where a cover glass is bonded to asemiconductor wafer via an adhesive pattern.

FIG. 12 is an end elevation along a line XII-XII in FIG. 11.

FIG. 13 is an end elevation showing an embodiment of a semiconductordevice according to the invention.

FIG. 14 is an end elevation showing an embodiment of a semiconductordevice according to the invention.

FIG. 15 is a cross-sectional view showing an embodiment of a CCD cameramodule according to the electronic component of the invention.

FIG. 16 is a cross-sectional view showing an embodiment of a CCD cameramodule according to the electronic component of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, the preferred embodiments of the invention will be describedin detail, but the invention is not to be construed as being limited bythe following embodiments.

The photosensitive adhesive composition according to this embodimentcontains a polymer soluble to an alkaline aqueous solution, aphoto-polymerizable compound and a photopolymerization initiator.

The polymer is preferably soluble to tetramethyl ammonium hydridesolution. For example. A polymer having a carboxyl group or hydroxygroup tends to be soluble to alkaline aqueous solution. The polymersoluble to alkaline-aqueous solution may be a polyimide having acarboxyl group.

The aforesaid polyimide comprises one, two or more polymers having animido skeleton in the main chain and a carboxyl group as a side chain.The acid value of the polyimide is 80 to 180 mg/KOH preferably. If theacid value of the polyimide is less than 80 mg/KOH, the solubility in analkali developer solution tends to fall, but if it exceeds 180 mg/KOH,there is a relatively high possibility that the adhesive layer willseparate from the adherend during developing. From this viewpoint, theacid value of the polyimide is more preferably 150 mg/KOH or less. Thephotosensitive adhesive composition preferably contains a thermosettingresin, described later, the acid value of the polyimide preferably being80 to 180 mg/KOH.

The polyimide having a carboxyl group can be obtained by the reaction ofa tetracarboxylic acid dianhydride and diamine having a carboxyl groupand an amino group. The carboxyl group of the diamine is therebyintroduced into the polyimide. By selecting the type of diamine, andsuitably adjusting the ratio of diamine and reaction conditions, theacid value can be arranged to be 80 to 180 mg or 80 to 150 mg/KOH.

The reaction (condensation reaction) between the tetracarboxylic aciddianhydride and diamine can be performed by any known method as will beunderstood by a person skilled in the art. For example, in thisreaction, an addition reaction is first carried out betweentetracarboxylic acid dianhydride and diamine in equimolar orapproximately equimolar proportions in an organic solvent at a reactiontemperature of 80° C. or preferably 0 to 60° C. The addition order ofeach component is arbitrary. As the reaction proceeds, the viscosity ofthe reaction solution rises gradually, and a polyamide acid which is aprecursor of the polyimide is produced. The molecular weight of thispolyamide acid can also be adjusted by heating and depolymerizing at atemperature of 50 to 80° C. The polyimide is obtained by performing adehydration ring closure of the polyamide acid. The dehydration ringclosure can be performed by a thermal ring closure by the action ofheat, or a chemical ring closure using a dehydrating agent.

Regarding the ratio of tetracarboxylic acid dianhydride to diamine, thetotal amount of diamine is preferably within the limits of 0.5 to 2.0moles and more preferably 0.8 to 1.0 moles relative to a total amount oftetracarboxylic acid dianhydride of 1.0 mole. If the ratio of diamineexceeds 2.0 moles, numerous polyimide oligomers having a terminal aminogroup are produced, and if it is less than 0.5 moles, numerous polyimideoligomers having a terminal carboxyl group are produced. If the amountof these polyimide oligomers increases, the weight average molecularweight of polyimide decreases and various properties, such as the heatresistance of the photosensitive adhesive composition, are easilyimpaired. By adjusting the aforesaid ratio, the polyimide can bearranged to have a weight average molecular weight within the limits of5000 to 150000.

To improve solubility in an alkaline aqueous solution, the diamine usedto synthesize the polyimide includes preferably the aromatic diamineexpressed by the aforesaid general formula (I) or (II).

To reduce Tg of the polyimide and reduce heat stress, it is still morepreferred that the diamine includes the aliphatic ether diamine of theaforesaid general formula (III). Specific examples of the aliphaticether diamine of formula (III) are the diamines expressed by thefollowing chemical formulae (IIIa), (IIIb) or (IIIc). Among these, fromthe viewpoint of obtaining sticking properties at low temperatures andgood adhesion to the adherend, the aliphatic ether diamine of formula(Ma) is preferred.

Commercial examples of an aliphatic ether diamine are Jeffamine “D-230”,“D-400”, “D-2000”, “D-4000”, “ED-600”, “ED-900”, “ED-2001”, “EDR-148”(product names) from Sun Techno Chemical, and the polyether ether amines“D-230”, “D-400”, “D-2000” (product names) from BASF.

In order to further enhance re-adhesiveness after light exposure, it ispreferable to use the siloxane diamine expressed by the aforesaidgeneral formula (IV).

Examples of the siloxane diamine expressed by the chemical formula (IV),when n₂ in formula is 1, are1,1,3,3-tetramethyl-1,3-bis(4-aminophenyl)disiloxane,1,1,3,3-tetraphenoxy-1,3-bis(4-aminoethyl)disiloxane,1,1,3,3-tetraphenyl-1,3-bis(2-aminoethyl)disiloxane,1,1,3,3-tetraphenyl-1,3-bis(3-aminopropyl)disiloxane,1,1,3,3-tetramethyl-1,3-bis(2-aminoethyl)disiloxane,1,1,3,3-tetramethyl-1,3-bis(3-aminopropyl)disiloxane,1,1,3,3-tetramethyl-1,3-bis(3-aminobutyl)disiloxane, and1,3-dimethyl-1,3-dimethoxy-1,3-bis(4-aminobutyl)disiloxane.Corresponding examples when n₂ is 2, are 1,1,3,3,5,5-hexamethyl-1,5-bis(4-aminophenyl)trisiloxane,1,1,5,5-tetraphenyl-3,3-dimethyl-1,5-bis(3-aminopropyl)trisiloxane,1,1,5,5-tetraphenyl-3,3-dimethoxy-1,5-bis(4-aminobutyl)trisiloxane,1,1,5,5-tetraphenyl-3,3-dimethoxy-1,5-bis(5-aminopentyl)trisiloxane,1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis(2-aminoethyl)trisiloxane,1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis(4-aminobutyl)trisiloxane,1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis(5-aminopentyl)trisiloxane,1,1,3,3,5,5-hexamethyl-1,5-bis(3-aminopropyl)trisiloxane,1,1,3,3,5,5-hexaethyl-1,5-bis(3-aminopropyl)trisiloxane, and1,1,3,3,5,5-hexapropyl-1,5-bis(3-aminopropyl)trisiloxane.

These diamines may be used alone, or two or more may be used together.In this case, it is preferred that the aromatic diamine expressed by thegeneral formula (I) or (II) is 10 to 50 mole % of the total diamine,that the siloxane diamine expressed by the general formula (IV) is 1 to20 mole % (still more preferably 5 to 10 mole %) of the total diamine,and that the aliphatic ether diamine expressed by the general formula(III) is 10 to 90 mole % of the total diamine. By this means, the acidvalue of the polyimide can usually be arranged to be 80 to 180 mg/KOH or80 to 150 mg/KOH. If the siloxane diamine is less than 1 mole % of thetotal diamine, re-adhesiveness after light exposure tends to decrease,whereas if it exceeds 20 mole %, solubility in the alkali developersolution tends to decrease. If the aliphatic ether diamine is less than10 mole % of the total diamine, Tg of the polyimide tends to increaseand low temperature workability (sticking properties at lowtemperatures) tend to decrease, whereas if it exceeds 90 mole %, voidstend to be occur during thermocompression bonding.

The diamine may further contain a diamine other than those mentionedabove, for example, o-phenylenediamine, m-phenylenediamine,p-phenylenediamine, 3,3′-diaminodiphenylether, 3,4′-diaminodiphenylether, 4,4′-diaminodiphenylether, 3,3′-diaminodiphenylmethane,3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether methane,bis(4-amino-3,5-dimethylphenyl)methane,bis(4-amino-3,5-diisopropylphenyl) methane,3,3′-diaminodiphenyldifluoromethane, 3,4′-diaminodiphenyldifluoromethane, 4,4′-diaminodiphenyl difluoromethane,3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone,4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfide,3,4′-diaminodiphenylsulfide, 4,4′-diaminodiphenylsulfide,3,3′-diaminodiphenylketone, 3,4′-diaminodiphenylketone,4,4′-diaminodiphenylketone, 2,2-bis(3-aminophenyl)propane,2,2′-(3,4′-diaminodiphenyl)propane, 2,2-bis(4-aminophenyl)propane,2,2-bis(3-aminophenyl)hexafluoropropane,2,2-(3,4′-diaminodiphenyl)hexafluoropropane,2,2-bis(4-aminophenyl)hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene,1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene,3,3′-(1,4-phenylenebis(1-methylethylidene))bis-aniline,3,4′-(1,4-phenylenebis(1-methylethylidene))bis-aniline,4,4′-(1,4-phenylenebis(1-methylethylidene))bis-aniline,2,2-bis(4-(3-aminophenoxy)phenyl)propane,2,2-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane,2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane,bis(4-(3-aminoethoxy)phenyl)sulfide,bis(4-(4-aminoethoxy)phenyl)sulfide,bis(4-(3-aminoethoxy)phenyl)sulfone, bis(4-(4-aminoethoxy)phenylsulfone,1,3-bis(aminomethyl)cyclohexane, and2,2-bis(4-aminophenoxyphenyl)propane.

The tetracarboxylic acid dianhydride used as starting material tosynthesize the polyimide is preferably purified by recrystallizationfrom acetic anhydride to suppress decrease in adhesive properties.Alternatively, tetracarboxylic acid dianhydride may be dried by heatingat a temperature lower 10 to 20° C. than the melting point for 12 hoursor more. The purity of tetracarboxylic acid dianhydride can be evaluatedfrom the difference of endothermic starting temperature and endothermicpeak temperature measured by a differential scanning calorimeter (DSC).It is preferable to use carboxylic acid dianhydride purified byrecrystallization or drying so that this difference is less than 20° C.,but more preferably less than 10° C., to synthesize the polyimide. Theendothermic starting temperature and endothermic peak temperature aremeasured under the conditions of sample amount: 5 mg, heating rate: 5°C./min, measurement atmosphere: nitrogen, using a DSC (DSC-7, PerkinElmer Co.).

The tetracarboxylic acid dianhydride may be, for example, pyromelliticacid dianhydride, 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride,2,2′,3,3′-biphenyltetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethanedianhydride, bis(2,3-dicarboxy phenyl)methane dianhydride,bis(3,4-dicarboxyphenyl)methane dianhydride,bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, bis(3,4-dicarboxy phenyl)etherdianhydride, benzene-1,2,3,4-tetracarboxylic acid dianhydride,3,4,3′,4′-benzophenone tetracarboxylic acid dianhydride,2,3,2′,3′-benzophenone tetracarboxylic acid dianhydride,3,3,3′,4′-benzophenone tetracarboxylic acid dianhydride,1,2,5,6-naphthalene tetracarboxylic acid dianhydride,1,4,5,8-naphthalene tetracarboxylic acid dianhydride,2,3,6,7-naphthalene tetracarboxylic acid dianhydride,1,2,4,5-naphthalene tetracarboxylic acid dianhydride,2,6-dichloronapthalene-1,4,5,8-tetracarboxylic acid dianhydride,2,7-dichloronapthalene-1,4,5,8-tetracarboxylic acid dianhydride,2,3,6,7-tetrachloronapthalene-1,4,5,8-tetracarboxylic acid dianhydride,phenanthrene-1,8,9,10-tetracarboxylic acid dianhydride,pyradine-2,3,5,6-tetracarboxylic acid dianhydride, thiophene2,3,5,6-tetracarboxylic acid dianhydride, 2,3,3′,4′-biphenyltetracarboxylic acid dianhydride, 3,4,3′,4′-biphenyl tetracarboxylic aciddianhydride, 2,3,2′,3′-biphenyl tetracarboxylic acid dianhydride,bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride,bis(3,4-dicarboxyphenyl)methylphenylsilane dianhydride,bis(3,4-dicarboxyphenyl)diphenylsilane dianhydride,1,4-bis(3,4-dicarboxyphenyldimethylsilyl)benzene dianhydride,1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldicyclohexanedianhydride, p-phenylene bis(trimellitate anhydride), ethylene tetracarboxylic acid dianhydride, 1,2,3,4-butane tetracarboxylic aciddianhydride, decahydronaphthalene-1,4,5,8-tetracarboxylic aciddianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic acid dianhydride,cyclopentane-1,2,3,4-tetracarboxylic acid dianhydride,pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride,1,2,3,4-cyclobutane tetracarboxylic acid dianhydride,bis(exo-bicyclo[2,2,1]heptane)-2,3-dicarboxylic acid dianhydride,bicyclo-[2,2,2]-octo-7-ene-2,3,5,6-tetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,2,2-bis[4-(3,4-dicarboxyphenyl)phenyl]propane dianhydride,2,2-bis(3,4-dicarboxy phenyl)hexafluoropropane dianhydride,2,2-bis[4-(3,4-dicarboxyphenyl)phenyl]hexafluoropropane dianhydride,4,4′-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride,1,4-bis(2-hydroxyhexafluoro isopropyl)benzene bis(trimelliticanhydride), 1,3-bis(2-hydroxy hexafluoroisopropyl)benzenebis(trimellitic anhydride),5-(2,5-dioxotetrahydrofuril)-3-methyl-3-cyclohexene-1,2-dicarboxylicacid dianhydride, and tetrahydrofurane-2,3,4,5-tetracarboxylic aciddianhydride.

To impart solubility in solvents, the tetracarboxylic acid dianhydridesexpressed by the following chemical formulae (V) or (VI) are preferred.In this case, the proportion of tetracarboxylic acid dianhydrideexpressed by these formulae is preferably 50 mole % or more relative to100 mole % of total tetracarboxylic acid dianhydrides. If thisproportion is less than 50 mole %, the solubility improvement effecttends to decrease.

The aforesaid tetracarboxylic acid dianhydrides may be used alone, ortwo may be used together.

The weight average molecular weight of the polyimide is preferablywithin the limits of 5000 to 150000, more preferably 20000 to 50000, andstill more preferably 30000 to 40000. If the weight average molecularweight of the polyimide is less than 5000, film-forming properties tendto decrease. If it exceeds 150000, solubility in an alkaline developersolution decreases and developing time tends to become long. By settingthe weight average molecular weight of polyimide to 5000 to 150000, theheating temperature (die bonding temperature) when the semiconductordevice is bonded to an adherend, such as a supporting substrate forsemiconductor device mounting, can be arranged low. The aforesaid weightaverage molecular weight is a weight average molecular weight measuredin terms of polystyrene using high performance liquid chromatography(e.g., “C-R4A” (product name), from Shimadzu Laboratories Inc.).

The glass transition temperature (hereafter, “Tg”) of the polyimidepreferably lies within the range of 30° C. to 150° C. If Tg is less than30° C., there is a tendency for voids to occur during compressionbonding. If Tg exceeds 150° C., the adherend sticking temperature andthe compression bonding temperature after light exposure increase, andthere is a tendency to damage surrounding parts. Tg is the peaktemperature of tan δ when measuring a film using a viscoelasticitymeasuring apparatus (Rheometrix Co.).

The photo-polymerizable compound is not particularly limited providedthat it is a compound which polymerizes by irradiation of radiation suchas ultraviolet light or an electron beam. The photo-polymerizablecompound is preferably a compound having an acrylate group or amethacrylate group. Examples of the photo-polymerizable compound aremethyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate,2-ethylhexyl methacrylate, pentenylacrylate, tetrahydrofurfurylacrylate, tetrahydrofurfuryl methacrylate, diethylene glycol diacrylate,triethylene glycol diacrylate, tetraethylene glycol diacrylate,diethylene glycol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, trimethylol propane diacrylate,trimethylol propane triacrylate, trimethylol propane dimethacrylate,trimethylol propane trimethacrylate, 1,4-butanediol diacrylate,1,6-hexane diol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol triacrylate, pentaerythritoltetraacrylate, pentaerythritol trimethacrylate, pentaerythritoltetramethacrylate, diheptaerythritol hexaacrylate, diheptaerythritolhexamethacrylate, styrene, divinylbenzene, 4-vinyltoluene,4-vinylpyridine, N-vinyl pyrrolidone, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,3-acryloyloxy-2-hydroxy propane,1,2-methacryloyloxy-2-hydroxy propane, methylene bisacrylamide,N,N-dimethylacrylamide, N-methylol acrylamide, triacrylate oftris(beta-hydroxyethyl)isocyanurate, the compound expressed by thefollowing general formula (10), urethane acrylate or urethanemethacrylate, and urea acrylate. R₃ and R₄ in formula (10) representsindependently a hydrogen atom or methyl group, and q and r representsindependently an integer equal to 1 or more.

Urethane acrylate and urethane methacrylate are produced for example byreaction of a diol, the isocyanate compound expressed by the followinggeneral formula (21) and the compound expressed by the following generalformula (22):

In formula (21), s is 0 or 1, and R₅ is a divalent or trivalent organicgroup having 1 to 30 carbon atoms. In formula (22), R₆ is a hydrogenatom or a methyl group, and R₇ is an ethylene or propylene group.

Urea methacrylate is produced by for example the reaction of the diamineexpressed by the following general formula (31) and the compoundexpressed by the following general formula (32):

In formula (31), R₈ is a divalent organic group having 2 to 30 carbonatoms. In formula (32), t is 0 or 1.

In addition to the aforesaid compounds, photo-polymerizable copolymershaving an ethylenic unsaturated group in a side chain, obtained by anaddition reaction of a compound having at least one ethylenicunsaturated group and a functional group such as an oxirane ring,isocyanate group, hydroxyl group and carboxyl group with a vinylcopolymer having a functional group, may be used.

These photo-polymerizable compounds may be used alone, or two or moremay be used together. Among these, the photo-polymerizable compoundsexpressed by the aforesaid general formula (10) are preferred from theviewpoint that they impart solvent resistance after curing, and urethaneacrylate and urethane methacrylate are preferred from the viewpoint thatthey impart flexibility after curing.

The molecular weight of the photo-polymerizable compound is preferably2000 or less. If the molecular weight exceeds 2000, solubility of thephotosensitive adhesive composition in an alkaline aqueous solutiondecreases, tackiness of the adhesive film decreases, and it is difficultto stick the film to an adherend, such as a semiconductor wafer, at lowtemperature.

The content of the photo-polymerizable compound is preferably 20 to 80weight parts, but more preferably 30 to 60 weight parts, relative to 100weight parts of the polyimide. If the amount of photo-polymerizablecompound exceeds 80 weight parts, the photo-polymerizable compound whichhas polymerized causes adhesive properties after thermocompressionbonding to decrease. If it is less than 5 weight parts, solventresistance after light exposure becomes low and it is difficult to forma pattern.

The photopolymerization initiator, to improve sensitivity when a patternis formed, preferably has an absorption band at 300 to 400 nm. Examplesof the photopolymerization initiator are aromatic ketones such asbenzophenone, N,N′-tetramethyl-4,4′-diaminobenzophenone (Michler'sketone), N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzophenone,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2,2-dimethoxy-1,2-diphenylethane-1-one,1-hydroxy-cyclohexyl-phenyl-ketone,2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropanone-1,2,4-diethylthioxanthone,2-ethyl anthraquinone and phenanthrene quinone, benzoin ethers such asbenzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether,benzoins such as methyl benzoin and ethyl benzoin, benzyl derivativessuch as benzyl dimethyl ketal, 2,4,5-triaryl imidazole dimers such as2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer, acridine derivatives such as9-phenylacridine and 1,7-bis(9,9′-acridinyl)heptane, and bis-acylphosphine oxides such asbis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentyl phosphine oxide andbis(2,4,6-trimethyl benzoyl)-phenyl phosphine oxide. These may be usedalone, or two or more may be used together.

The amount of photopolymerization initiator is not particularly limited,but is usually 0.01 to 30 weight parts relative to 100 weight parts ofpolyimide.

The photosensitive adhesive composition preferably further contains athermosetting resin. In the invention, thermosetting resin means areactive compound which can crosslink due to the action of heat.Examples of such compounds are epoxy resin, cyanate resin, bismaleimideresin, phenol resin, urea resin, melamine resin, alkyd resin, acrylicresin, unsaturated polyester resin, diallyl phthalate resin, siliconeresin, resorcinol formaldehyde resin, xylene resin, furan resin,polyurethane resin, ketone resin, triallyl cyanurate resin,polyisocyanate resin, resin containing tris(2-hydroxyethyl)isocyanurate,resin containing triallyl trimelitate, thermosetting resin synthesizedfrom cyclopentadiene, and thermosetting resin obtained by trimerizationof an aromatic dicyanamide. Among these, from the viewpoint of impartingsuperior adhesive force at high temperature, epoxy resin, cyanate resinand bismaleimide resin are preferred, and from the viewpoint of handlingproperties and compatibility with polyimide, epoxy resin is particularlypreferred. These thermosetting resins may be used alone, or two or moremay be used together.

The epoxy resin preferably has at least two epoxy groups in themolecule. From the viewpoint of curing properties or the properties ofthe cured material, glycidyl ether pf phenol type epoxy resins areparticularly preferred. Examples of such epoxy resins are the glycidylether of bisphenol A, AD, S or F, glycidyl ether of hydrogenatedbisphenol A, glycidyl ether of the ethylene oxide adduct of bisphenol A,glycidyl ether of the propylene oxide adduct of bisphenol A, glycidylether of phenol novolak resin, glycidyl ether of cresol novolak resin,glycidyl ether of bisphenol A novolak resin, glycidyl ether ofnaphthalene resin, glycidyl ethers with 3 functional groups or 4functional groups, glycidyl ether of dicycloheptadiene phenol resin,glycidyl esters of dimeric acids, glycidyl amines with 3 functionalgroups or 4 functional groups, and the glycidyl amine of naphthaleneresin. These may be used alone, or two or more may be used together.

Examples of cyanate resins are 2,2′-bis(4-cyanatephenyl)isopropylidene,1,1′-bis(4-cyanatephenyl)ethane,bis(4-cyanate-3,5-dimethylphenyl)methane,1,3-bis[4-cyanatephenyl-1-(1-methylethylidene)]benzene, cyanatedphenol-di cyclopentane diene adduct, cyanated novolak, bis(4-cyanatephenyl)thioether, bis(4-cyanate phenyl)ether, resorcinol dicyanate,1,1,1-tris(4-cyanate phenyl)ethane, and 2-phenyl-2-(4-cyanatephenyl)isopropylidene. These may be used alone, or two or more may beused together.

Examples of bismaleimide resins are o-, m- or p-bismaleimidebenzene,4-bis(p-maleimidocumyl)benzene, 1,4-bis(m-maleimidocumyl)benzene and themaleimide compounds expressed by the following general formulae (40),(41), (42) or (43). These may be used alone, or two or more may be usedtogether.

In formula (40), R₄₀ is —O—, —CH₂—, —CF₂—, —SO₂—, —S—, —CO—, —C(CH₃)₂—or —C(CF₃)₂—, the four R₄₁ are each a hydrogen atom, lower alkyl groupor lower alkoxy group, fluorine, chlorine or bromine, and the two Z₁ areboth dicarboxylic acid residues having an ethylenic unsaturated doublebond.

In formula (41), R₄₂ is —O—, —CH₂—, —CF₂—, —SO₂—, —S—, —CO—, —C(CH₃)₂—or —C(CF₃)₂—, the four R₄₃ are each a hydrogen atom, lower alkyl group,lower alkoxy group, fluorine, chlorine or bromine, and the two Z₂ areboth dicarboxylic acid residues having an ethylenic unsaturated doublebond.

In formula (42), x is an integer from 0 to 4, and the plural Z₃ are eachdicarboxylic acid residues having an ethylenic unsaturated double bond.

In formula (43), the two R₄₄ are both a divalent hydrocarbon group, theplural R₄₅ are each a monovalent hydrocarbon group, the two Z₄ are bothdicarboxylic acid residues having an ethylenic unsaturated double bond,and y is an integer equal to 1 or more.

Z₁, Z₂, Z₃ and Z₄ in the formulae (40)-(43) may be a maleic acid residueor citraconic acid residue.

Examples of the bismaleimide resin expressed by formula (41) are4,4-bismaleimidediphenyl ether, 4,4-bismaleimide diphenylmethane,4,4-bismaleimide-3,3′-dimethyl-diphenylmethane, 4,4-bismaleimidediphenylsulfone, 4,4-bismaleimide diphenyl sulfide, 4,4-bismaleimidediphenylketone, 2′-bis(4-maleimidophenyl)propane, 4-bismaleimidediphenylfluoromethane and1,1,1,3,3,3-hexafluoro-2,2-bis(4-maleimidophenyl)propane.

Examples of the bismaleimide resin expressed by formula (42) arebis[4-(4-maleimidophenoxy)phenyl]ether,bis[4-(4-maleimidophenoxy)phenyl]methane,bis[4-(4-maleimidophenoxy)phenyl]fluoromethane,bis[4-(4-maleimidophenoxy)phenyl]sulfone,bis[4-(3-maleimidophenoxy)phenyl]sulfone,bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(4-maleimidophenoxy)phenyl]ketone, 2-bis[4-(4-maleimidophenoxy)phenyl]propane and1,1,1,3,3,3-hexafluoro-2,2-bis[4-(4-maleimidophenoxy)phenyl]propane.

When a thermosetting resin is used, in order to cure the resin, anadditive such as a curing agent, curing promoter or catalyst may besuitably added to the photosensitive adhesive composition. When acatalyst is added, a co-catalyst can also be used if required.

If an epoxy resin is used, it is preferable to use an epoxy resin curingagent or curing agent promoter, and more preferable to use themtogether. The curing agent may be for example a phenolic compound, analiphatic amine, an alicyclic amine, an aromatic polyamine, a polyamide,an aliphatic acid anhydride, an alicyclic acid anhydride, an aromaticacid anhydride, dicyandiamide, an organic acid dihydrazide, a borontrifluoride amine complex, imidazole or derivative thereof, a tertiaryamine, or a phenolic compound having at least two phenolic hydroxylgroups in the molecule. Among these, from the viewpoint of superiorsolubility in an alkaline aqueous solution, a phenolic compound havingat least two phenolic hydroxyl groups in the molecule is preferred.

Examples of the phenolic compound having at least two phenolic hydroxylgroups in the molecule are phenol novolak resin, cresol novolak resin,t-butyl phenol novolak resin, dicycloheptadiene cresol novolak resin,dicycloheptadiene phenol novolak resin, xylylene-modified phenol novolakresin, naphthol novolak resin, trisphenol novolak resin, tetrakis phenolnovolak resin, bisphenol A novolak resin, poly-p-vinyl phenol resin andphenol aralkyl resin.

The curing promoter is not particularly limited provided that itpromotes the curing of the epoxy resin, but examples are imidazoles,dicyandiamide derivatives, dicarboxylic acid dihydrazide, triphenylphosphine, tetraphenylphosphoniumtetraphenyl borate, 2-ethyl-4-methylimidazole-tetraphenyl borate, and1,8-diazabicyclo[5.4.0]undecene-7-tetraphenyl borate.

The amount of epoxy resin curing agent is preferably 0 to 200 weightparts relative to 100 weight parts of epoxy resin, and the amount ofcuring agent promoter is preferably 0 to 50 weight parts relative to 100weight parts of epoxy resin.

When a cyanate resin is used as the thermosetting resin, it ispreferable to use a catalyst and a co-catalyst if required. The catalystmay be for example a metal salt or metal complex of cobalt, zinc orcopper, and the co-catalyst is preferably a phenolic compound such as analkylphenol, bisphenol compounds or phenol novolak.

When a bismaleimide resin is used as the thermosetting resin, it ispreferably to use a radical polymerization agent as the curing agent.Examples of a radical polymerization agent are acetyl cyclohexylsulfonylperoxide, isobutyryl peroxide, benzoyl peroxide, octanoylperoxide, acetyl peroxide, dicumyl peroxide, cumene hydroperoxide, andazobisisobutyronitrile. The amount of radical polymerization agent usedis preferably 0.01 to 1.0 weight parts relative to 100 weight parts ofbismaleimide resin.

The photosensitive adhesive composition may contain a suitable couplingagent to increase adhesive strength. The coupling agent may be forexample a silane coupling agent or titanium coupling agent, but amongthese, a silane coupling agent imparts a high adhesive strength and istherefore preferred.

If a coupling agent is used, its amount is preferably 0 to 50 weightparts and more preferably 0 to 20 weight parts relative to 100 weightparts of polyimide. If this exceeds 50 weight parts, there is a tendencyfor the storage stability of the photosensitive adhesive composition todecrease.

Examples of a silane coupling agent are vinyltrimethoxysilane,vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-isocyanate propyltriethoxysilane,3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxy silane,3-ureidopropyltriethoxysilane,N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propane amine,N,N′-bis[3-(trimethoxysilyl)propyl]ethylenediamine, polyoxyethylenepropyltrialkoxysilane and polyethoxydimethylsiloxane. These may be usedalone, or two or more may be used together.

The photosensitive adhesive composition may contain a filler. The fillermay be for example a metal filler such as silver powder, gold powder orcopper powder, a non-metal filler such as silica, alumina, boronnitride, titania, glass, iron oxide, aluminum boride or ceramics, or anorganic filler such as carbon or rubber filler.

The aforesaid fillers may be used according to their desired function.For example, a metal filler is added to impart conductivity orthixotropic properties to the adhesive film, a nonmetallic inorganicfiller is added to impart low thermal expansion properties and lowmoisture absorption to the adhesive film, and an organic filler is addedto impart toughness to the adhesive film. A metal filler, nonmetalinorganic filler and organic filler may be used alone, or two or moremay be used together. If the fillers are blended together, kneading maybe performed by a suitable combination of dispersing machines such as anordinary agitator, kneader, three-roll mill and ball mill.

If a filler is used, its amount is preferably 1000 weight parts or less,and more preferably 500 weight parts or less, relative to 100 weightparts of polyimide. The lower limit is not particularly limited, but itis usually 1 weight part. If the filler amount exceeds 1000 weightparts, there is a tendency for adhesiveness to decrease.

When a silicon chip is bonded to a glass substrate via thisphotosensitive adhesive composition, it should preferably provide ashear adhesive strength at 25° C. of 5 MPa or more. If the shearadhesive strength at 25° C. is less than 5 MPa, it is difficult toobtain an adhesive bond which can withstand the external forces appliedwhen assembling electronic parts. Further, when a silicon chip is bondedto a glass substrate via this photosensitive adhesive composition, thephotosensitive adhesive composition should preferably provide a shearadhesive strength at 260° C. of 0.5 MPa or more. If the shear adhesivestrength at 260° C. is less than 0.5 MPa, it is difficult to suppressdebonding or destruction during high temperature heating when thesemiconductor device obtained by using the photosensitive adhesivecomposition is mounted on the substrate by soldering.

The shear adhesive strength at 25° C. or 260° C. is the shear adhesivestrength (maximum stress) measured by using a laminate comprising asilicon chip of 3 mm×3 mm×400 μm thickness and a glass substrate of 10mm×10 mm×0.55 mm thickness bonded together via an adhesive layer of thephotosensitive adhesive composition of thickness approx. 40 μm which hasbeen exposed and heated as a test peace, the shear adhesive strength ismeasured when an external force in the shear direction is applied to alateral wall of the silicon chip under the conditions of measurementtemperature: 25° C. or 260° C., measurement rate: 50 μm/sec andmeasurement height: 50 μm. The measuring device is an adhesive strengthtester “Dage-4000” from Dage Co.

The aforesaid laminate is typically prepared by the following procedure.First, an adhesive film of the photosensitive adhesive composition isformed on a polyethylene terephthalate film (PET film), and thisadhesive film is laminated on a silicon wafer of size 6 inches,thickness 400 μm. The lamination is performed under the conditions ofline pressure: 4 kgf/cm, feed rate: 0.5 m/min while heating to 80° C.using a device having a roll and a support. Next, the laminated adhesivefilm is irradiated from the PET film side by ultraviolet light of 1000mJ/cm². Then, the silicon wafer is cut together with the adhesive film,and a silicon chip with an adhesive film of size 3 mm×3 mm is thusobtained. After the PET film is peeled off and a pressure-sensitivedicing tape is laminated on the adhesive film, the silicon wafer is cutusing a dicer. The silicon chip with adhesive film is then mounted on aglass substrate of thickness 10 mm×10 mm×0.55 mm such that the adhesivefilm is in contact with the glass substrate, and it is thermocompressionbonded on a 120° C. heating plate under the conditions of 500 gf for 10seconds. The adhesive film is further cured by heating in a 160° C. ovenfor 3 hours. By the above procedure, the aforesaid laminate formeasuring shear adhesive strength is obtained.

The storage modulus of the photosensitive adhesive composition at 100°C. after light exposure is preferably 0.01 to 10 MPa. If the storagemodulus is less than 0.01 MPa, resistance to the heat and pressureapplied during thermocompression bonding after pattern-forming decreasesand the pattern is easily crushed, whereas, if it exceeds 10 MPa,re-adhesiveness after exposure decreases, and the temperature requiredto obtain sufficient adhesive strength during thermocompression bondingto the adherend after pattern-forming becomes higher.

The value of the storage modulus is obtained by measuring the dynamicviscoelasticity of a test piece of the photosensitive resin compositionexposed to light. The dynamic viscoelasticity is measured under theconditions of heating rate: 5° C., frequency: 1 Hz, measurementtemperature: 50° C. to 200° C. The measuring device is, for example, a“RSA-2” viscoelasticity analyzer, Rheometrix Co.

The test piece for dynamic viscoelasticity measurement is typicallyprepared as follows. First, an adhesive sheet having a PET film and anadhesive film of thickness approx. 40 μm formed on one surface thereof,is cut to a size of 35 mm×10 mm, and it is irradiated by ultravioletlight from the PET film side under the condition of light exposure: 1000mJ/cm² using a high precision parallel exposure device (ORCManufacturing Co.). After exposure, the PET film is peeled off and theaforesaid test piece is thus obtained.

The storage modulus of the photosensitive adhesive composition at 260°C. after light exposure and heat curing is preferably 1 MPa or more. Ifthis storage modulus is less than 1 MPa, when the semiconductor deviceobtained using the photosensitive adhesive composition is mounted on asubstrate by soldering, it is difficult to suppress debonding ordestruction during high temperature heating.

The value of the storage modulus is obtained by measuring the dynamicviscoelasticity of a test piece comprising the photosensitive resincomposition after light exposure and heat curing. The dynamicviscoelasticity is measured under the conditions of heating rate: 5° C.,frequency: 1 Hz, measurement temperature: −50° C. to 300° C. Themeasuring device is, for example, a “RSA-2” viscoelasticity analyzer,Rheometrix Co.

The adhesive film for the aforesaid dynamic viscoelasticity measurementis typically obtained by heat curing in a 160° C. oven for 3 hours afterexposed under identical conditions to those mentioned above for thepreparation of a test piece for dynamic viscoelasticity measurementafter light exposure.

The temperature at which the mass percentage reduction of thephotosensitive adhesive composition in a thermogravimetric analysisafter light exposure and heat curing is 5% (hereafter “5% mass decreasetemperature”), is preferably 260° C. or more. If the 5% mass decreasetemperature is less than 260° C., it tends to be difficult to suppressdebonding or destruction during high temperature heating when thesemiconductor device obtained using the photosensitive adhesivecomposition is mounted on a substrate by soldering. Further, thepossibility of soiling surrounding material or parts due to volatileconstituents generated during the heating, becomes high.

The 5% mass decrease temperature is the temperature at which the masspercentage reduction relative to the initial mass is 5% in athermogravimetric analysis performed under the conditions of heatingrate: 10° C./min, air flow rate: 80 mL/min, measurement temperature: 40°C. to 400° C. The sample for thermogravimetric analysis is prepared byfinely crushing an adhesive film, light-exposed and heated underidentical conditions to those described for the storage modulus afterheat curing was performed following light exposure, using a mortar. Themeasuring device is, for example, a Simultaneous ThermogravimetricDifferential Thermal Analyzer “EXSTAR 6300”, S.I.I. Nanotechnology Co.

The above properties can be obtained by preparing the photosensitiveadhesive composition using the polyimide, photo-polymerizable compoundand photopolymerization initiator, and the thermosetting resin andfiller if required, and adjusting the types and blending ratio thereof.

FIG. 1 is a cross-sectional view showing an embodiment of the adhesivefilm according to the invention. Adhesive film 1 shown in FIG. 1 isobtained by forming the aforesaid photosensitive adhesive composition inthe shape of a film. FIG. 2 is a cross-sectional view showing anembodiment of the adhesive sheet according to the invention. Adhesivesheet 10 shown in FIG. 2 comprises a substrate 3, and an adhesive layerconsisted of the adhesive film 1 provided on one surface thereof.

The adhesive film 1 can be obtained by for example blending thepolyimide, photo-polymerizable compound, photopolymerization initiatorand other components if required in an organic solvent, kneading themixture to prepare a varnish, and after forming a layer of this varnishon the substrate 3, drying the varnish layer by heating and thenremoving the substrate 3. It can also be stored and used as the adhesivesheet 10 without removing the substrate 3.

The aforesaid blending and kneading may be performed by suitablycombining dispersion machines such as an ordinary agitator, kneader,three-roll mill and ball mill. If a thermosetting resin is used, dryingis performed at a temperature at which the thermosetting resin does notfully react during drying and at which the solvent vaporizes to asufficient extent. Specifically the varnish layer is dried by heatingusually at 60 to 180° C. for 0.1 to 90 minutes.

The temperature at which the thermosetting resin does not fully react isa temperature below the peak temperature of the heat of reaction whenmeasured under the conditions of sample amount 10 mg, heating rate 5°C./min, measuring atmosphere: air, using a DSC (e.g., “DSC-7” (productname), Perkin Elmer Co.).

The organic solvent, i.e., the varnish solvent, used for preparation ofthe varnish is not particularly limited provided that the materials canbe dissolved or distributed homogeneously. Examples aredimethylformamide, toluene, benzene, xylene, methyl ethyl ketone,tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, dioxane,cyclohexanone, ethyl acetate and N-methyl-pyrrolidinone.

The thickness of the varnish layer is preferably 1 to 100 μm. If thisthickness is less than 1 μm, there is a tendency for adherend fixingability to decrease, and if it exceeds 100 μm, residual volatilematerial in the obtained adhesive film 1 tends to increase.

The residual volatile material in the adhesive film 1 is preferably 10mass % or less. If this residual volatile material exceeds 10 mass %,voids easily remain in the adhesive layer due to foaming byvolatilization of solvent from heating during assembly, and wetproofreliability easily decreases. There is also an increased possibility ofcontaminating surrounding material or parts due to volatile constituentsgenerated during heating. This residual volatile constituent iscalculated by the equation:the residual volatile material (M%)={(M2−M1)/M1}×100,

wherein the initial mass of an adhesive film cut to a size of 50 mm×50mm is M1, and the mass after heating this adhesive film in a 160° C.oven for 3 hours is M2.

The substrate 3 is not particularly limited provided that it canwithstand the aforesaid drying conditions. For example, a polyesterfilm, polypropylene film, polyethylene terephthalate film, polyimidefilm, polyether imide film, polyether naphthalate film and methylpentene film can be used as the substrate 3. The film used as thesubstrate 3 may be a multilayer film which combines two or more types,and the surface thereof may be treated with a silicone type or silicatype release agent.

FIG. 3 is a top view showing an embodiment of a semiconductor wafer withadhesive layer according to the invention. FIG. 4 is an end elevationalong a line IV-IV of FIG. 3. A semiconductor wafer 20 with adhesivelayer shown in FIG. 3, 4 comprises a semiconductor wafer 5 and anadhesive layer 1 consisted of the aforesaid photosensitive adhesivecomposition provided on one surface thereof. The semiconductor wafer 5is typically a silicone wafer.

The semiconductor wafer 20 with adhesive layer is obtained by laminatingthe adhesive film 1 on the semiconductor wafer 5 while heating. Sincethe adhesive film 1 is a film comprising the aforesaid photosensitiveadhesive composition, it can be stuck to the semiconductor wafer 20 atlow temperatures, for example, room temperature to approx. 100° C.

The semiconductor wafer 20 with adhesive layer may be used tomanufacture electronic components such as a CCD camera module or CMOScamera module via a step wherein an adherend is bonded to thesemiconductor wafer 5 via the adhesive layer 1. Hereafter, a case ofmanufacturing a CCD camera module will be described. A CMOS cameramodule can be manufactured by an identical method.

FIG. 5 is a top view showing an embodiment of an adhesive patternaccording to the invention. FIG. 6 is an end elevation along a lineVI-VI of FIG. 5. On the semiconductor wafer 5 which is the adherend, anadhesive pattern 1 a shown in FIG. 5, 6 is formed along the sides of anapproximate square surrounding plural effective pixel regions 7 on thesemiconductor wafer 5.

FIG. 7 is a top view showing an embodiment of an adhesive patternaccording to the invention. FIG. 8 is an end elevation along a lineVIII-VIII of FIG. 8. In the semiconductor wafer 5 which is the adherend,an adhesive pattern 1 b shown in FIG. 7, 8 is patterned so that anapproximately square opening in which the effective pixel regions 7 areexposed on the semiconductor wafer 5 is formed.

The adhesive patterns 1 a, 1 b are formed by forming the adhesive layerconsisted of the photosensitive adhesive composition on thesemiconductor wafer 5 as adherend to obtain the semiconductor wafer withadhesive layer 20, light-exposing the adhesive layer 1 via a photomask,and after exposure, developing the adhesive layer 1 with an alkalineaqueous solution. Therefore, the adhesive patterns 1 a, 1 b comprise thephotosensitive adhesive composition after light exposure.

Next, a cover glass 9 as another adherend is bonded to the semiconductorwafer 5 via the adhesive pattern 1 a or 1 b. FIG. 9 is a top viewshowing a state where the cover glass 9 is bonded to the semiconductorwafer 5 via the adhesive pattern 1 a. FIG. 10 is an end elevation alonga line X-X of FIG. 9. FIG. 11 is a top view showing a state where thecover glass 9 is bonded to the semiconductor wafer 5 via the adhesivepattern 1 b. FIG. 12 is an end elevation along a line XI-XI of FIG. 11.The cover glass 9 is bonded to the semiconductor wafer 5 with theheat-cured adhesive pattern 1 a or 1 b sandwiched therebetween. Thecover glass 9 is mounted on the adhesive pattern 1 a or 1 b, and thecover glass 9 is bonded by thermocompression. The adhesive pattern 1 aor 1 b functions as an adhesive for adhering the cover glass 9, and alsofunction as a spacer for ensuring there is sufficient space surroundingthe effective pixel regions 7.

After adhering the cover glass 9, a semiconductor device 30 a shown inFIG. 13 or a semiconductor device 30 b shown in FIG. 14 is obtained bydicing along the broken line D. The semiconductor device 30 a comprisesthe semiconductor chip 5, effective pixel regions 7, adhesive pattern(adhesive layer) 1 a and cover glass 9. The semiconductor device 30 bcomprises the semiconductor chip 5, effective pixel regions 7, adhesivepattern (adhesive layer) 1 b and cover glass 9.

FIG. 15 is a cross-sectional view showing an embodiment of a CCD cameramodule according to the electronic component of the invention. A CCDcamera module 50 a shown in FIG. 15 is an electronic componentcomprising the semiconductor device 30 a as a solid-state image sensingdevice. The semiconductor device 30 a is bonded to a supportingsubstrate 15 for semiconductor device mounting via a die bonding film11. The semiconductor device 30 a is electrically connected to anexternal connection terminal via a wire 12.

A CCD camera module 50 comprises a lens 40 situated immediately abovethe effective pixel region 7, side walls 16 which enclose the lens 40together with the semiconductor device 30 a, and insertion members 17interposed between the lens 40 and side walls 16 with the lens 40inserted on the supporting substrate 15 for semiconductor devicemounting.

FIG. 16 is a cross-sectional view showing an embodiment of a CCD cameramodule according to the electronic component of the invention. A CCDcamera module 50 b shown in FIG. 16, instead of the construction of theaforesaid embodiment where the semiconductor device is bonded using adie bonding film, has a construction wherein the semiconductor device 30a is bonded to the supporting substrate 15 for semiconductor devicemounting via solder 13.

EXAMPLES

Hereafter, the invention will be described in more detail referring tospecific examples, but it should be understood that the invention is notto be construed as being limited to the following examples.

Synthesis of PI-1

7.6 g of 3,5-diaminobenzoic acid (hereafter, “DABA”) and NMP wereintroduced in a flask provided with a stirrer, thermometer and nitrogenreplacement device. Next, a solution of 15.5 g of 4,4′-oxydiphthalicacid dianhydride (hereafter, “ODPA”) in NMP was dripped in the aforesaidflask while adjusting the temperature of the reaction system so that itdid not exceed 50° C. After dripping was complete, the mixture wasstirred at room temperature for 5 hours. Next, a reflux condenser withwater receiver was attached to this flask, xylene was added, thetemperature was raised to 180 degrees and this temperature wasmaintained for 5 hours. A brown solution was thus obtained. The obtainedsolution was cooled to room temperature, introduced into distilled waterand reprecipitated. The obtained sediment was dried with a vacuum dryer,and a polyimide (hereafter “polyimide PI-1”) was thus obtained.

When the GPC was measured with DMF as the mobile phase, the weightaverage molecular weight (polystyrene conversion) of polyimide PI-1 was72000. The acid value computed from the blending ratio of the startingmaterials for polyimide PI-1 was 130 mg/KOH.

The acid value of the polyimide may be computed as follows based on theblending ratio of starting materials. For the tetracarboxylic aciddianhydride used as starting material, let the molecular weight beAw_(n) (Aw₁, Aw₂, Aw₃, . . . for each compound used), and let the molarnumber be Am_(n) (Am₁, Am₂, Am₃, . . . for each compound used). For thediamine used as starting material, let the molecular weight be Bw_(n)(Bw₁, Bw₂, Bw₃, . . . for each compound used), and let the molar numberbe Bm_(n) (Bm₁, Bm₂, Bm₃, . . . for each compound used). The molarnumber of total tetracarboxylic acid dianhydride is A_(all)(A_(all)=ΣAm_(n)), and the molar number of total diamine is B_(all)(B_(all)=ΣBm_(n)). When DABA is used as a carboxyl-group-containingdiamine, the acid value may be computed from the equation: Acid value(mg/KOH)=1/[Σ{(Aw_(n)+Bw_(n)−36)×(Am_(n)/A_(all))×(Bm_(n)/B_(all))}]×55.1×1000.When 5,5′-methylene-bis(anthranilic acid) (MBAA) is used as acarboxyl-group-containing diamine, the acid value may be computed fromthe equation: Acid value(mg/KOH)=1/[Σ{(Aw_(n)+Bw_(n)−36)×(Am_(n)/A_(all))×(Bm_(n)/B_(all))}]×55.1×1000×2.When no carboxyl-group-containing diamine is used, the acid value isconsidered to be less than 80.

A polyimide film of thickness 40 μm was manufactured by coating avarnish comprising a mixture of polyimide PI-1 with a solvent on a PETfilm which had been surface-treated with a mold release silicone, anddrying. For a test piece of size 35 mm×10 mm cut out from this film,measurements were made at a heating rate of 5° C./min using a “RSA-2”(product name) viscoelasticity meter, frequency 1 Hz and measurementtemperature −50° C. to 300° C., and the temperature at which tan δshowed a local maximum was taken as Tg of the polyimide PI-1. If tan δshowed a local maximum at plural temperatures, the temperature at whichit showed the largest local maximum was taken as Tg. The Tg of thepolyimide PI-1 was 200° C.

Synthesis of Polyimide PI-2

6.84 g of DABA, 9.99 g of aliphatic ether diamine (“ED2000” (productname), BASF, molecular weight 1998) and NMP were introduced in a flaskprovided with a stirrer, thermometer and nitrogen replacement device.Next, a solution containing 16 g of ODPA dissolved in NMP was dripped inthe flask while adjusting the temperature of the reaction system so thatit did not exceed 50° C. All the remaining operations were identical tothose for the synthesis of PI-1, and a polyimide (hereafter “polyimidePI-2”) was thus obtained.

The weight average molecular weight of polyimide PI-2 and Tg weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 51000, and Tg was 140° C. The acidvalue computed from the blending ratio of starting materials forpolyimide PI-2 was 90 mg/KOH.

Synthesis of Polyimide PI-3

2.28 g of DABA, 15.16 g of aliphatic ether diamine (“ED400” (productname), BASF, molecular weight 433) and NMP were introduced in a flaskprovided with a stirrer, thermometer and nitrogen replacement device.Next, a solution containing 16 g of ODPA dissolved in NMP was dripped inthe flask while adjusting the temperature of the reaction system so thatit did not exceed 50° C. All the remaining operations were identical tothose for the synthesis of PI-1, and a polyimide (hereafter “polyimidePI-3”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-3 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 47000, and Tg was 50° C. The acidvalue computed from the blending ratio of starting materials forpolyimide PI-3 was 88 mg/KOH.

Synthesis of Polyimide PI-4

1.9 g of DABA, 15.16 g of aliphatic ether diamine (“ED400” (productname), BASF, molecular weight 433), 0.87 g of1,1,3,3-tetramethyl-1,3-bis(4-aminophenyl)disiloxane (“LP-7100” (productname), Shin-Etsu Chemical Co., molecular weight 348.4) and NMP wereintroduced in a flask provided with a stirrer, thermometer and nitrogenreplacement device. Next, a solution containing 16 g of ODPA dissolvedin NMP was dripped in the flask while adjusting the temperature of thereaction system so that it did not exceed 50° C. All the remainingoperations were identical to those for the synthesis of PI-1, and apolyimide (hereafter “polyimide PI-4”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-4 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 33000, and Tg was 55° C. The acidvalue computed from the blending ratio of starting materials forpolyimide PI-4 was 88 mg/KOH.

Synthesis of Polyimide PI-5

5.4 g of m-phenyldiamine and NMP were introduced in a flask providedwith a stirrer, thermometer and nitrogen replacement device. Next, asolution containing 15.5 g of ODPA dissolved in NMP was dripped in theflask while adjusting the temperature of the reaction system so that itdid not exceed 50° C. All the remaining operations were identical tothose for the synthesis of PI-1, and a polyimide (hereafter “polyimidePI-5”) was thus obtained.

The weight average molecular weight of polyimide PI-5 and Tg weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 68000, and Tg was 210° C. Thepolyimide PI-5 was not synthesized using a diamine containing acarboxylic acid, so its acid value was considered to be less than 80mg/KOH.

Synthesis of Polyimide PI-6

99.9 g of aliphatic ether diamine (“ED2000” (product name), BASF,molecular weight 1998) and NMP were introduced in a flask provided witha stirrer, thermometer and nitrogen replacement device. Next, a solutioncontaining 15.5 g of ODPA dissolved in NMP was dripped in the flaskwhile adjusting the temperature of the reaction system so that it didnot exceed 50° C. All the remaining operations were identical to thosefor the synthesis of PI-1, and a polyimide (hereafter “polyimide PI-6”)was thus obtained.

The weight average molecular weight and Tg of polyimide PI-6 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 74000, and Tg was 10° C. Thepolyimide PI-6 was not synthesized using a diamine containing acarboxylic acid, so its acid value was considered to be less than 80mg/KOH.

Synthesis of Polyimide PI-7

49.95 g of aliphatic ether diamine (“ED2000” (product name), BASF,molecular weight 1998), 8.71 g of1,1,3,3-tetramethyl-1,3-bis(4-aminophenyl)disiloxane (“LP-7100” (productname), Shin-Etsu Chemical Co., molecular weight 348.4) and NMP wereintroduced in a flask provided with a stirrer, thermometer and nitrogenreplacement device. Next, a solution containing 16 g of ODPA dissolvedin NMP was dripped in the flask while adjusting the temperature of thereaction system so that it did not exceed 50° C. All the remainingoperations were identical to those for the synthesis of PI-1, and apolyimide (hereafter “polyimide PI-7”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-7 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 45000, and Tg was 30° C. Thepolyimide PI-7 was not synthesized using a diamine containing acarboxylic acid, so its acid value was considered to be less than 80mg/KOH.

Synthesis of Polyimide PI-8

2.15 g of 5,5′-methylene-bis(anthranilic acid) (hereafter, “MBAA”,molecular weight 286.28), 15.59 g of aliphatic ether diamine (“ED400”(product name), BASF, molecular weight 433), 2.26 g of1,1,3,3-tetramethyl-1,3-bis(4-aminophenyl)disiloxane (“LP-7100” (productname), Shin-Etsu Chemical Co., molecular weight 348.4) and NMP wereintroduced in a flask provided with a stirrer, thermometer and nitrogenreplacement device. Next, a solution containing 17 g of ODPA dissolvedin NMP was dripped in the flask while adjusting the temperature of thereaction system so that it did not exceed 50° C. All the remainingoperations were identical to those for the synthesis of PI-1, and apolyimide (hereafter “polyimide PI-8”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-8 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 28000, and Tg was 30° C.

The acid value computed from the blending ratio of starting materialsfor polyimide PI-8 was 167 mg/KOH.

Synthesis of Polyimide PI-9

2.10 g of 1,12-diamine dodecane (hereafter, “DDO”), 17.98 g of aliphaticether diamine (“ED2000” (product name), BASF, molecular weight 1998),2.61 g of 1,1,3,3-tetramethyl-1,3-bis(4-aminophenyl)disiloxane(“LP-7100” (product name), Shin-Etsu Chemical Co., molecular weight348.4) and NMP were introduced in a flask provided with a stirrer,thermometer and nitrogen replacement device. Next, a solution containing15.62 g of 4,4′-(4,4′-isopropylidene diphenoxy)bis(phthalic aciddianhydride) (hereafter, “BPADA”) dissolved in NMP was dripped in theflask while adjusting the temperature of the reaction system so that itdid not exceed 50° C. All the remaining operations were identical tothose for the synthesis of PI-1, and a polyimide (hereafter “polyimidePI-9”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-9 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 70000, and Tg was 53° C. Thepolyimide PI-9 was not synthesized using a diamine containing acarboxylic acid, so its acid value was considered to be less than 80mg/KOH.

Synthesis of Polyimide PI-10

6.83 g of 2,2-bis(4-aminophenoxyphenyl)propane (hereafter, “BAPP”), 3.40g of 4,9-dioxadecane-1,12-diamine (hereafter, “B-12”) and NMP wereintroduced in a flask provided with a stirrer, thermometer and nitrogenreplacement device. Next, a solution containing 17.40 g of decamethylenebistrimellitate dianhydride (hereafter, “DBTA”) dissolved in NMP wasdripped in the flask while adjusting the temperature of the reactionsystem so that it did not exceed 50° C. All the remaining operationswere identical to those for the synthesis of PI-1, and a polyimide(hereafter “polyimide PI-10”) was thus obtained.

The weight average molecular weight and Tg of polyimide PI-10 weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 89000, and Tg was 73° C. Thepolyimide PI-10 was not synthesized using a diamine containing acarboxylic acid, so its acid value was considered to be less than 80mg/KOH.

Synthesis of Polyimide PI-11

14.3 g of MBAA and NMP were introduced in a flask provided with astirrer, thermometer and nitrogen replacement device. Next, a solutioncontaining 16 g of ODPA dissolved in NMP was dripped in the flask whileadjusting the temperature of the reaction system so that it did notexceed 50° C. All the remaining operations were identical to those forthe synthesis of PI-1, and a polyimide (hereafter “polyimide PI-11”) wasthus obtained.

The weight average molecular weight of polyimide PI-11 and Tg weremeasured under identical conditions to those for polyimide PI-1. Theweight average molecular weight was 82000, and Tg was 180° C. The acidvalue computed from the blending ratio of starting materials forpolyimide PI-11 was 197 mg/KOH.

TABLE 1 and TABLE 2 show the blending ratios (molar ratios) forpolyimide synthesis, and the test results for the obtained polyimides.The values of the blending ratios in Table 1 are values (mole %) whentotal tetracarboxylic acid dianhydride and total diamine are taken asreferences, respectively.

TABLE 1 PI-1 PI-2 PI-3 PI-4 PI-5 PI-6 PI-7 Tetracarboxylic ODPA 100 100100  100  100 100 100  acid dianhydride Aromatic DABA 100 90 30 25 — — —diamine of formula (I) Aliphatic ED2000 — 10 — — — 100 50 ether diamineED400 — — 70 70 — — — of formula (III) Siloxane LP7100 — — —  5 — — 50diamine of formula (IV) m-phenylenediamine — — — — 100 — — Weightaverage 72000  51000 47000   33000   68000  74000  45000   molecularweight Acid value (mg/KOH) 130 90 88 88 <80 <80 <80  Tg (° C.) 200 14050 55 210  10 30

TABLE 2 PI-8 PI-9 PI-10 PI-11 Tetracarboxylic ODPA 100  — — 100 acidBPADA — 100  — — dianhydride DBTA — — 100  — Aromatic MBAA 15 — — 100diamine of formula (II) Aliphatic ED400 72 30 — — ether diamine offormula (III) Siloxane LP7100 13 35 — — diamine of formula (IV) DDO — 35— — BAPP — — 50 — B-12 — — 50 — Weight average 28000   70000   89000  82000  molecular weight Acid value (mg/KOH) 167  <80  <80  197 Tg (° C.)30 53 73 180

Example 1

Polyimide PI-1, ethoxylated bisphenol A dimethacrylate (“BPE-100”(product name) by Shin Nakamura Chemicals Co.) as photo-polymerizablecompound and bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (“I-819”(product name), Chiba Specialty Chemicals Co.) as photopolymerizationinitiator were blended uniformly in cyclohexanone to manufacture anadhesive film-forming varnish so that the composition (weight parts)shown in Table 3 was obtained. This varnish was applied on to a PET filmwhich had been surface-treated with mold release silicone, dried, and anadhesive film of thickness 40 μm was thereby formed.

Examples 2 to 7, Comparative Examples 1 to 8

An adhesive film was produced in an identical way to that of Example 1,except that the starting materials and compositions shown in TABLE 3 or4, respectively, were used.

The details of the starting materials shown in Tables 3, 4 are asfollows.

BPE-100: Shin Nakamura Chemicals, ethoxylated bisphenol A dimethacrylate

U-2PPA: Shin Nakamura Chemical Co., urethane acrylate

YDF-8170: Toto Chemical Co., bisphenol F epoxy resin

ESCN-195: Sumitomo Chemical Co., cresol novolak solid epoxy resin

H-1: Meiwa Chemical Co., phenol novolak

R972: Nippon Aerogel Co., hydrophobic fumed silica (mean particlediameter: approx. 16 nm)

TABLE 3 Examples 1 2 3 4 5 6 7 Polyimide PI-2(90) 100 100 — — — — —(acid value) PI-3(100) — — 100 — — — — PI-4(88) — — — 100 100 100 —PI-8(167) — — — — — — 100 Photopolymerizable BPE-100 20 20 20 20 15 4035 compound U-2PPA — — — — 15 40 35 Photopolymerization I-819 3 3 3 3 33 3 initiator Epoxy resin YDF-8170 — 15 15 15 15 15 15 ESCN-195 — — — —— 5 5 Curing agent H-1 — — — — 5 5 5 Filler R972 — — — — 5 5 5 Filmproperties Pattern-forming A A A A A A A properties Sticking propertiesA A A A A A A at low temperatures Shear adhesive  25° C. 13 17 15 20 3030 20 strength (MPa) 260° C. <0.1 0.5 0.4 0.5 0.6 0.9 0.5 Elasticmodulus at 100° C. 0.05 0.07 0.1 1 2 5 4 after light exposure (MPa)Elastic modulus at 260° C. Measurement 5 5 5 11 13 13 after heat curing(MPa) not possible. 5% weight decrease temperature 330 286 292 290 294297 296 (° C.) Water absorption rate (%) 1.9 1.9 1.8 1.8 1.7 1.5 2.3

TABLE 4 Comparative Examples 1 2 3 4 5 6 7 8 Polyimide PI-1(130) 100 — —— — — — (acid value) PI-2(90) — 100 — — — — — — PI-5(<80) — — 100 — — —— — PI-6(<80) — — — 100 — — — — PI-7(<80) — — — — 100 — — — PI-9(<80) —— — — — 100 — — PI-10(<80) — — — — — — 100 — PI-11(197) — — — — — — —100 Photopolymerizable BPE-100 — — — 20 20 — — 20 compound U-2PPA — — —— — — — — Photopolymerization I-819 — — — 3 3 — — 3 initiator Epoxyresin YDF-8170 — — — 15 15 — — 15 ESCN-195 — — — — — 25 25 — Curingagent H-1 — — — — — 13 13 5 Film properties Pattern-forming C C C C C CC C properties Sticking properties C C C A A A C C at low temperaturesShear adhesive  25° C. — 12 — 10 20 30 30 30 strength (MPa) 260° C. —<0.1 — 0.3 0.4 8 10 <0.1 Elastic modulus at 100° C. 2000 <0.01 2500 0.030.03 0.2 4.3 1800 after light exposure (MPa) Elastic modulus at 260° C.2 Measurement 10 3 6 1.7 2.3 10 after heat curing (MPa) not possible. 5%weight decrease temperature 320 180 100 280 285 380 430 297 (° C.) Waterabsorption rate (%) 3.0 2.3 1.0 1.9 1.7 0.6 0.3 3.5

For the obtained adhesive films, pattern-forming properties, stickingproperties at low temperatures and shear adhesive strength wereevaluated by the methods shown below. The evaluation results arecollectively shown in TABLES 3, 4.

(1) Pattern-Forming Properties

An adhesive film was laminated by pressurizing it with a roller onto asilicon wafer (diameter 6 inches, thickness 400 μm), and a mask was laidthereupon. After light exposure with a high precision parallel device(ORC Manufacturing Co.), spray developing was performed using a 2.38%solution of tetramethyl ammonium hydride (TMAH). After developing, anexamination was performed to verify whether a pattern (line width 1 mm)had been formed. If a pattern had been formed, the result was designatedas A, and if a pattern had not been formed, the result was designated asC.

(2) Sticking Properties at Low Temperatures

An adhesive film was laminated on a back side (opposite to a supportingplatform) of silicon wafer on a supporting platform (diameter 6 inch,thickness 400 μm) by pressurizing with a roller (temperature 100° C.,linear pressure 4 kgf/cm, feed rate 0.5 m/min). The PET film was peeledoff, and a “Upirex” (product name) polyimide film of thickness 80 μm,width 10 mm and length 40 mm was laminated by pressurizing with a rollerunder identical conditions to the above. For the sample thus obtained, a90° peel test was performed at room temperature using a “Strograph E-S”(product name) rheometer, and the peel strength between the adhesivefilm and Upirex was measured. Samples having a peel strength of 2N/cm ormore were designated A, and samples having less than 2N/cm weredesignated C.

(3) Adhesiveness (Shear Adhesive Strength)

An adhesive film was laminated on a silicon wafer (diameter 6 inch,thickness 400 μm) under the conditions of 80° C., linear pressure: 4kgf/cm, feed rate: 0.5 m/min using a device having a roll and a support.Next, the laminate was irradiated by ultraviolet light under thecondition of light exposure: 1000 mJ/cm² from the PET film side using ahigh precision parallel exposure device (ORC Manufacturing Co.). The PETfilm was peeled away, and a pressure-sensitive dicing tape was laminatedon the adhesive film. The silicon wafer was cut out together with theadhesive film to a size of 3 mm×3 mm using a dicer, and a silicon chipon which the adhesive film was laminated, was thus obtained. Thissilicon chip was mounted on a glass substrate of 10 mm×10 mm×0.55 mmthickness with the adhesive film sandwiched therebetween, and bonded bythermocompression on a 120° C. heating plate under 500 gf for 10seconds. Next, it was heated in a 160° C. oven for 3 hours to heat-curethe adhesive film. The maximum stress for the sample, when an externalforce in the shear direction was applied to the lateral wall of thesilicon chip on a hot plate heated at 25° C. or 260° C. under theconditions of measurement rate: 50 μm/sec and measurement height: 50 μm,using a “Dage-4000” adhesion tester, Dage Co., was taken to be the shearadhesive strength at 25° C. or 260° C.

(4) Elastic Modulus at 100° C. after Light Exposure

An adhesive film was cut to a size of 35 mm×10 mm and irradiated byultraviolet light from the PET film side under the condition of lightexposure: 1000 mJ/cm² using a high precision parallel exposure device(ORC Manufacturing Co.). Dynamic viscoelasticity was measured using a“RSA-2” viscoelasticity analyzer, Rheometrix Co., under the conditionsof heating rate: 5° C./min, frequency: 1 Hz, measurement temperature:−50° C. to 200° C. using an adhesive film after light exposure fromwhich the PET film had been peeled off as test piece. The storagemodulus at 100° C. was obtained from this dynamic viscoelasticitymeasurement.

(5) Elastic Modulus at 260° C. after Heat-Curing

An adhesive film was cut to a size of 35 mm×10 mm, and irradiated byultraviolet light from the PET film side under the condition of lightexposure: 1000 mJ/cm² using a high precision parallel exposure device(ORC Manufacturing Co.). After peeling off the PET film, the adhesivefilm was cured by heating in a 160° C. oven for 3 hours. Dynamicviscoelasticity was measured using a “RSA-2” viscoelasticity analyzer,Rheometrix Co., under the conditions of heating rate: 5° C./min,frequency: 1 Hz, measurement temperature: −50° C. to 300° C. using thecured adhesive film as test piece. The storage modulus at 260° C. wasobtained from this dynamic viscoelasticity measurement.

(6) 5% Mass Decrease Temperature

An adhesive film was irradiated by ultraviolet light from the PET filmside under the condition of light exposure: 1000 mJ/cm² using a highprecision parallel exposure device (ORC Manufacturing Co.). After thePET film was peeled off, the adhesive film was cured by heating in a160° C. oven for 3 hours. A thermogravimetric analysis was performed onthe powder obtained by finely crushing the cured adhesive film under theconditions of heating rate: 10° C./min, air flow rate: 80 mL/min,measurement temperature: 40° C. to 400° C., using an “EXSTAR 6300”Simultaneous Thermogravimetric Differential Thermal Analyzer, S.I.I.Nanotechnology Co. From this thermogravimetric analysis, the temperatureat which the mass percentage reduction relative to the initial mass is5% (5% mass decrease temperature), was evaluated.

As shown in TABLE 3, it is seen that the adhesive films of the exampleshad superior pattern-forming properties and low temperature stickingproperties. Also, the adhesive films of the examples showed highadhesive strength by compression after light exposure, and were alsosuperior in respect of re-adhesiveness after light exposure. On theother hand, as shown in TABLE 4, the adhesive films of the comparativeexamples were not adequate in respect of pattern-forming properties, lowtemperature sticking properties or re-adhesiveness.

The photosensitive adhesive composition of the invention has a largedissolution rate in alkali developer solution, superior pattern-formingproperties using an alkali developer solution, and high re-adhesivenessafter light exposure. Further, the adhesive film of the invention can bestuck to an adherend at relatively low temperature, and since thermaldamage to surrounding material is thereby suppressed, a reliablesemiconductor device and electronic component are obtained.

1. A method for producing a semiconductor device, comprising the stepsof: forming an adhesive layer on a semiconductor wafer by sticking anadhesive film to the semiconductor wafer; forming an adhesive pattern bylight-exposing and developing the adhesive layer; and bonding anadherend to the semiconductor wafer via the adhesive pattern.
 2. Themethod according to claim 1, wherein the adhesive film is stuck to thesemiconductor wafer at a temperature of 100° C. or lower.
 3. The methodaccording to claim 1, further comprising the step of dicing a laminateof the adherend and the semiconductor wafer obtained by the bondingstep.
 4. The method according to claim 1, wherein the adherend is aglass substrate.
 5. The method according to claim 1, wherein theadhesive layer is formed of a photosensitive adhesive composition havinga storage modulus at 100° C., after light exposure, of 0.01 to 10 MPa,and a storage modulus at 260° C., after light exposure and heat curing,of at least 1 MPa.
 6. The method according to claim 1, wherein theadhesive layer is formed of a photosensitive adhesive composition. 7.The method according to claim 6, wherein the photosensitive resincomposition contains a polymer soluble to an alkaline aqueous solution.8. The method according to claim 7, wherein the polymer is soluble totetramethyl ammonium hydride solution.
 9. The method according to claim1, wherein said developing is conducted using an alkaline aqueoussolution.